Apparatus and method of spinal implant and fusion

ABSTRACT

An apparatus and method of performing a minimally invasive posterior spine fusion. More specifically an apparatus with a handle and a forked head on the distal end of the handle is used to grasp implant material and introduce the material to an implant site. The shaft of the apparatus is shaped so as to allow the affixation of a drill guide and drill while simultaneously holding the implant material in the implant site. After removal of the boring tools and assembly of the fusing element, the apparatus can be selectively removed from the implant site. A method of achieving facet joint fusion with near simultaneous fixation is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/120,260, filed on Dec. 5, 2008, and U.S. ProvisionalPatent Application No. 61/186,683, filed on Jun. 12, 2009, the entiredisclosures of which are incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

This disclosure relates to orthopedic surgery, and more specifically toapparatus and methods for placing an implant into a patient, forexample, to promote an intervertebral fusion.

BACKGROUND OF THE INVENTION

Individuals who suffer degenerative disc disease, natural spinedeformations, a herniated disc, spine injuries or other spine disordersmay require surgery on the affected region to relieve the individualfrom pain and prevent further injury to the spine and nerves. Spinalsurgery may involve removal of damaged joint tissue, insertion of atissue implant and/or fixation of two or more adjacent vertebral bodies.The surgical procedure will vary depending on the nature and extent ofthe injury.

For patients with varying degrees of degenerative disc disease and/ornerve compression with associated lower back pain, spinal fusionsurgery, or lumbar arthrodesis (“fusion”) is an effective method andcommonly used to treat the degenerative disease. Fusion commonlyinvolves distracting and/or decompressing one or more intervertebralspaces, followed by removing any associated facet joints or discs, andthen joining or “fusing” two or more adjacent vertebra together. Thisfusion typically occurs with the assistance of an autograft or allograftbone graft. In certain operations, the fusion may also be assisted by aparticular spinal implant or one or more bioactive materials.

Fusion of vertebral bodies involves fixation of two or more adjacentvertebrae. This procedure may be performed through introduction of rodsor plates, and screws or other devices into a vertebral joint to joinvarious portions of a vertebra to a corresponding portion on an adjacentvertebra. Fusion may occur in the lumbar, interbody or cervical spineregion of a patient. A fusion is designed to stop and/or eliminate allmotion in the spinal segment by destruction of some or all of the jointsin that segment, and further utilizing bone graft material and/or rigidimplantable fixation devices for securing the adjacent vertebrae. Byeliminating movement, back pain and further degenerative disc diseasemay be reduced or avoided. Fusion requires tools for accessing thevertebrae and implanting the desired implant, bioactive material, etc.Such procedures often require introduction of additional tools toprepare a site for implantation. These tools may include drills, drillguides, debridement tools, irrigation devices, vises, clamps, cannulae,and other insertion/retraction tools.

Generally, there are five main types of lumbar fusion, including:posterior lumbar fusion (“PLF”), posterior lumbar interbody fusion(“PLIF”), anterior lumbar interbody fusion (“ALIF”), circumferential 360fusion, and transforaminal lumbar interbody fusion (“TLIF”). A posteriorapproach is one that accesses the surgical site from the patient's back,and an anterior approach is one that accesses the surgical site from thepatient's front or chest. There are similar approaches for fusion in theinterbody or cervical spine regions.

Certain procedures are designed to achieve fixation of vertebral bodies,for example, in the cervical spine region, through an anterior cervicalapproach. The main risks of the anterior approach are vascular injury,injury to the superior laryngeal nerve leading to hoarseness, injury tothe esophagus and spinal cord injury. Interbody bone grafts or cageshave been designed to fit between the vertebrae at the intervertebralspace and are often secured in position by anterior plating systems. Theanterior approach has been the mainstay for treatment of the majority ofcervical spine degenerative conditions, trauma or neurologicalcompression conditions related to disk herniation. The anterior approachis extensile and allows exposure of the front part of the cervical spinefrom C2-T1. The limitations of this approach are that posterior-basedpathology cannot be treated without fusion and that revision anteriorsurgery can be highly morbid because of damage to the vascular andneurological structures described. Since the esophagus is directly infront of the vertebral body involved in an anterior fusion, it isparticularly vulnerable to revision anterior surgery. Unrecognizedinjury to the esophagus can lead to mediastinitis, which has anattendant mortality rate of 80%. The more levels the surgeon attempts tofuse together, the greater the risk for a failure to fuse orpseudoarthrosis. The risk for at least one level of a three levelanterior fusion not healing is 50%.

Alternatively, a posterior approach to the cervical spine may be used todecompress the spinal canal or to allow for fusion. Posterior cervicalfusions are performed in a fashion distinct from the anterior interbodytechnique. The process involves decorticating the facet joint and itsattendant cartilage followed by application of bone graft between theleaves of the facet joint. Traditionally, posterior element wiringstabilized the motion segment. Lateral mass screws and plates or rodshave supplanted this technique. Posterior approaches suffer the samedisadvantages as posterior surgery in other areas of the spine withincreased morbidity associated with bleeding, infection, damage tonormal tissues and unsightly scars—issues which are not substantialconcerns with anterior neck operations. Posterior cervical operationsare much more painful than the anterior approach and in and ofthemselves necessitate longer hospital stays and longer postoperativerecovery. The most common indication for posterior cervical approachesare failure of the anterior fusion to heal. Other disadvantages oftraditional posterior cervical fusion include, for example, theincreased length of the procedure, the complexity and over-engineeredimplants used to carry out the procedure, and the possible requirementof a second procedure to remove the implantation device.

Posterior cervical spinal fusion techniques have not kept pace withminimally invasive techniques available for the posterior lumbar spineand this has led to its underutilization, particularly in instances ofpatients at high risk for pseudoarthrosis—cigarette smokers, patientswith multiple level fusions anteriorly or patients with hypothyroidism.The reason for this underutilization has to do with the difference inthe anatomy of the neck which make application of the lumbar designsimpractical and dangerous. A truly novel approach and instrumentationsystem is necessary in this scenario; it is not a simple matter of“miniaturizing” the lumbar designs. Posterior cervical fusion systemsare maximally invasive leading to substantial perioperative morbidity.They are over-engineered in terms of strength and do not take advantageof the mechanical stability afforded by anterior instrumentation appliedat the same time (or before in the instance of pseudoarthrosis).Posterior systems can be much smaller and less restrictive and stillaccomplish the goals of fusion. For example, simple wiring of theposterior elements in the face of an anterior pseudoarthrosis leads tosuccessful athrodesis in 80% of cases. Unfortunately, posterior wiringhas the unfortunate requirement of a formal posterior exposure with itsattendant morbidity. Finally, the minimally invasive approach to theposterior cervical spine fusion needs to account for the unique anatomicconcerns of the neurovascular and digestive anatomy as well as takeadvantage of the stability gained from the more easily performedanterior cervical fusion. These and other considerations are addressedby the present disclosure in more detail in the Summary and DetailedDescription of the Preferred Embodiments, and the appended Claims.

SUMMARY OF THE INVENTION

One aspect of certain embodiments of the present disclosure relates toproviding a minimally invasive method and apparatus for an implant to beplaced in the joint space in an intervertebral facet joint after theremoval of damaged joint tissue, and near simultaneous fixation ofadjacent vertebral bodies. Certain embodiments relate to a minimallyinvasive method and apparatus for implanting an implant between one ormore vertebral facet joints, and more particularly in the cervical spineregion.

Incorporated by reference in their entireties are the following U.S.patents and patent applications directed generally to methods andapparatus related to spinal procedures, thus providing writtendescription support for various aspects of the present disclosure. TheU.S. patents and pending applications incorporated by reference are asfollows: U.S. Pat. No. 7,406,775 to Funk, et al.; U.S. Pat. No.7,387,643 to Michelson; U.S. Pat. No. 7,341,590 to Ferree; U.S. Pat. No.7,288,093 to Michelson; U.S. Pat. No. 7,207,992 to Ritland; U.S. Pat.No. 7,077,864 Byrd III, et al.; U.S. Pat. No. 7,025,769 to Ferree; U.S.Pat. No. 6,719,795 to Cornwall, et al.; U.S. Pat. No. 6,364,880 toMichelson; U.S. Pat. No. 6,328,738 to Suddaby; U.S. Pat. No. 6,290,724to Marino; U.S. Pat. No. 6,113,602 to Sand; U.S. Pat. No. 6,030,401 toMarino; U.S. Pat. No. 5,865,846 to Bryan, et al.; U.S. Pat. No.5,569,246 to Ojima, et al.; U.S. Pat. No. 5,527,312 to Ray; and U.S.Patent Publication No. 2008/0255564 to Michelson.

In one embodiment of the present disclosure, an improved apparatus andmethod of providing fixation of adjacent vertebral bodies is provided byuse of a device which comprises a handle, an elongated shaft, and a headthat selectively grasps, for example, a bioactive material which isadapted to be inserted into the joint space at an intervertebral facetjoint. In one embodiment of the present disclosure, the device can beplaced in communication with a drill guide to direct a drill to thejoint region, upon which a drill is used to create a hole in, forexample, the facet joint. A facet screw may then be assembled into thehole. A specially designed screw both provides fixation for thevertebrae, and also helps to retain the implant material within thefacet joint. According to other embodiments described herein, the screwmay be omitted, or alternatively replaced with a staple or otherfastening device.

In one embodiment of the present disclosure, a method of posteriorspinal fixation includes using a device under microscopic control orloupe magnification to burr off the bottom of the facet joint. Curettesand rasps may be used to prepare the facet joint to a bleeding surface.A trial implant, the same size and shape of the final implant is placedin the facet joint, to confirm appropriate joint carpentry. Then thehead of the apparatus, preferably comprising a forked end attached to aflexible distal shaft, preferably a flexible shaft, is fitted withbioactive material, and is placed between the leaves of the joint. Theadjacent bone surfaces are then connected, preferably employing morethan just the bioactive material (e.g., via one or more devicesdescribed herein). For example, a drill guide may be lowered over theshaft of the apparatus until it is adjacent to the facet joint. Thedrill is used to create hole(s) through the facet joint. A speciallydesigned screw or other fastening device is then assembled through thehole(s) or otherwise adjacent the facet, thereby trapping (or otherwisesubstantially ensuring a desired amount is retained) the bioactivematerial in the joint. The apparatus is then removed, leaving thebioactive material in the joint space. This method is accomplished in aminimally invasive manner to provide near-simultaneous fixation of thevertebral bodies surrounding the facet joint.

According to this embodiment of the present disclosure, the apparatus isprovided with a head that has one or more tines creating a “fork” shapedend, and the head being in communication with a flexible shaft. Whilethis particular embodiment envisions the use of a “fork”, one of skillin the art will understand the more general scope of the inventionrelates to provision of implantable material to a desired predeterminedoperation site, employing a device that releasably secures preferablybioactive material that is shaped to conform with the general morphologyof the space provided in the facet joint. The head can be pre-fittedwith an implantable material, for example, a bioactive material in sucha manner so that the material can be easily manipulated into the facetjoint. The forked end may have a mechanism that enables it to releasethe material once a facet screw has secured the material in the joint.The apparatus may be constructed so that the forked end can bemanipulated, by way of the flexible shaft, in at least one dimensionrelative to the shaft. The apparatus may further be constructed topermit the forked end to comprise a first orientation, wherein thebioactive material is retained by the head of the apparatus, and asecond orientation, wherein the bioactive material is released from thehead of the apparatus. According to this embodiment, the surgeon mayselectively retain or release the bioactive material by operation of theapparatus.

The head of the apparatus can be any of a plurality of shapes, forexample, an arcuate shaped head, where the head is asymmetricallysecured to the distal shaft. Also by way of example but not limitation,a head may be comprised of a variably rigid material. The variably rigidmaterial may be designed to allow the bioactive material to be, forexample, frictionally or mechanically held in place, and released uponapplication of a particular force. In another embodiment of theapparatus, the head may be made of a semi-flexible material that iscapable of grasping the bioactive material and releasing the bioactivematerial when a particular force is applied, for example, a force in aparticular dimension, or, for example, once a particular torque istransmitted from the shaft to the head of the apparatus. Yet anotheraspect of the present disclosure is that the head itself is comprised ofthe implant material. Thus, for example, the head may be selectivelyattached to the shaft of the apparatus, and thereafter, selectivelydetached from the shaft of the material once the head is placed in theimplant site. According to this embodiment, the head is part of theimplant and remains in the patient with the implant material. One havingskill in the art will appreciate that the head may be selectivelyattached to the shaft, for example, by means that mechanically grasp thehead, means that attach by vacuum, means that attach by friction, andmeans that attach by magnetism, or other means known to those of skillin the art for attaching the head of an apparatus to the shaft of anapparatus.

In another embodiment of the design, the graft material is prefabricatedand combined with a semi-rigid material. This composite has a hexagonalend that fits into the metal handle of the drill guide section, whichallows introduction of the material into the joint and simple detachmentof the grafting material from the introduction tool. The hexagonal endhas a built-in angle corresponding to the angle of the facet joint.Accordingly, the angle is approximately 45 degrees in the cervicalspine, the angle is approximately 90 degrees in the thoracic spine, andthe angle is approximately 180 degrees in the lumbar spine.

The prefabricated complex of osteobiologic material insertion handle isa unique combination that allows for ease of insertion and maximizes thegrafting surface area. The handle portion can be an inert non-absorbablematerial including, for example, nylon or slowly absorbing poly gelacetate, either of which have the attachment of biomaterialincorporated. The extra-articular section of the composite can betrimmed at the joint surface once the joint has been stabilized by thescrew, which further secures the grafting material in place.

According to one embodiment of the present disclosure, the head may beselected from one or more bioactive materials, such that the head is theimplant. This bioactive implant may further comprise an absorbable band,which preferably attaches to the shaft via a resorbable connection,e.g., hex-shaped. According to alternate embodiments, the head mayfurther comprise multiple absorbable bands which assist in attaching thehead to the shaft. This configuration provides an implant that isdistinguishable from other spinal implants, which are made exclusivelyof a single type of material (e.g., bone, autographed bone, graphed,allograft bone graft, etc.) Thus, for example, the present inventionincludes a bioactive implant that includes more than one type ofmaterial, with certain embodiments including one or more absorbablebands in addition to other non-absorbable components. According to yetan another alternate embodiment, the bioactive implant materialcomprising one or more absorbable bands which attaches to the shaft viaa resorbable hex-shaped connector may be provided with a instrument headthat does not remain in the patient with the implant material. Thecomposite head-bioactive membrane complex with its hex-end may beconsidered a portal through which biologic activator materials may beused to inoculate the inserted graft material. One skilled in the artcan understand that the graft once inserted into the facet joint can bebiologically activated by direct injection of a stem cell preparation,bone marrow aspirat, commercial bone morphogenic protein or othermaterial to encourage fusion in the facet joint. In still otherembodiments, electrostimulation can be employed to assist in theregulation of bone morphogenic protein expression in bone cells via theapplication of fields generated by selective electric and/orelectromagnetic signals.

Yet another aspect of the present disclosure relates to the provision ofa distal end of a shaft of the apparatus that is flexible to allow, forexample, the user to maneuver the head and material to the implantationsite. One skilled in the art will appreciate that the flexible aspect ofcertain embodiments can be both passive and active in nature. Activeflexibility and manipulation in the distal end of the shaft mayincorporate, for example, the manipulative capabilities of an endoscope,including components for manipulation such as guidewires along thelongitudinal axis of the shaft of the apparatus. U.S. Pat. No. 5,704,892is incorporated by reference herein in its entirety for the purpose ofdemonstrating the manipulative capabilities of a surgical tool, such asthe one contemplated by this disclosure.

It is another aspect of the present disclosure that the distal end ofthe shaft be equipped with various other tools to aid in the procedure.Such tools may include, for example, devices used to assess thecondition of the implantation site and surrounding tissue. This mayinclude, for example, a device that transmits or provides an image orsignal which carries an image for visual inspection and photography.Such an image capture device may include, for example, a device toilluminate the implant site coupled with an image capture and/ortransmission device. Another tool may also include, for example, adevice that aids in irrigation or drainage of the surgical site, a toolused to sample or biopsy tissue. Still other embodiments of theinvention include methods and systems that employ image data capturingof particular aspects of a patient's anatomy along the spine. Forexample, image guided medical and surgical techniques such as thosedisclosed in U.S. Patent Publication No. 20090299477 to Clayton arehereby incorporated in their entirety by this reference. By employmentof such systems and/or methods, the tracking of components relative to aportion of the anatomy ensures that the surgeon positions the same in aselected portion of the anatomy and at a proper orientation in order tosupplement the surgeon's judgment with respect to proper surgicalprocedures.

In another embodiment of the present disclosure, the head of theapparatus is angled and is shaped to allow ideal access and placement ofthe implant in the joint. For example, the angle and shape of the headrelative to the shaft may be optimized for a particular implant site.The angle, for example, may be selectively variable or affixed. Thisangle may further depend on the specific vertebrae that form the implantsite. Since the spinal column is a curved structure, angle requirementsmay differ with each implant site. The angle may also depend on whichside of the vertebrae the implant is occurring.

Another factor may be whether the surgical approach to the joint is donefrom a superior or inferior approach. Yet another factor that may affectthe shape and angle of the head is the age or physiology of the patient.Yet another factor is the angle of approach to the implant site throughthe muscle or other tissue. For example, according to variousembodiments described in more detail herein, the use of angled cannulamay permit a surgeon to access multiple levels of vertebrae through asingle incision, in part by use of angled cannula to access facet jointsadjacent the facet joint aligned with the incision. One skilled in theart will appreciate that as surgical techniques and methods develop, theapparatus may be adapted, for example, to offer different angles ofintroduction to an implant site to be manufactured into different shapesand from materials, and to provide access to other devices.

One skilled in the art will appreciate that the end of the apparatusneed not be limited to a forked shape. The head may be of a forkedshape, for example, that consists of one or more tines, or alternativelymay be subs square or rectangular in shape. The head may also be, forexample, retractable in nature. The apparatus may be, for example,capable of being operated in an arthroscopic procedure. Forms anddesigns that relate to the provision of an end of an apparatus toperform particular functions including, for example, grasping amaterial, selectively releasing a material, maneuvering, providingaccess for other devices, and providing other surgical, evaluative,exploratory, educational or investigatory functions are herebyincorporated into this disclosure.

In another aspect of an embodiment of the present disclosure, the shaftof the apparatus may be curved and/or may have an angular aspect. Thisshape in the shaft may, for example, aid the surgeon in more comfortablyintroducing the head of the apparatus to the implant site, be shaped tobetter accommodate implantation sites on right or left sides of thebody, or be shaped to better accommodate right- or left-handed surgeons.The shaft of the apparatus may also be shaped to allow introduction ofan implant to the portion of the spine which is traditionally accessedby posterior means. One having skill in the art will appreciate that theshaft of the apparatus may have multiple angles and curved aspects whichenable aspects of embodiments of the present disclosure or aid inergonomics.

One having skill in the art will appreciate that embodiments of thepresent disclosure may have various sizes. The sizes of the variouselements of embodiments of the present disclosure may be sized based onvarious factors including, for example, the anatomy of the implantpatient, the person or other device operating the apparatus, the implantlocation, physical features of the implant including, for example, with,length and thickness, and the size of the drill or other surgical toolbeing used with the apparatus.

In yet another embodiment of the present disclosure, the head ismanufactured of a material and to dimensions that allow the head toserve as a spacer between the leaves of the joint at an implant site.The apparatus is then fitted with a device or other means to injectimplant material into the joint space. This implant material mayinclude, for example, a fast-curing epoxy or cement, a fast-curingbioactive cement, a cell culture, or other biologically inert substance.This injection may occur before, after, or during drilling and/orassembly of a screw into the joint space.

Alternatively, a screw is not required where the injected implantmaterial sufficiently provides mechanical support to the joint. Once theimplant material is injected into the joint space, the head and theapparatus may be removed from the implant site. Alternatively, the headmay be selectively detached from the shaft of the apparatus and remainin the joint space to, for example, provide mechanical support, or serveto encase the injected implant material. One having skill in the artwill appreciate the material and dimension requirements of the head andapparatus that will enable this embodiment.

The current disclosure is unique in that it integrates the process offacet joint fusion with near simultaneous fixation. Another uniquefeature is that the entire process can be performed using minimallyinvasive or endoscopic techniques. One of the features of the presentdisclosure is that it allows the majority of the joint to be preparedfor fusion (as opposed to <10% of the joint with, for example, a TruFusedowel). One embodiment of the present disclosure has a prefabricatedpiece of biomaterial shaped to fit into the regionally differentlyangled facet joints of the cervical, thoracic and/or lumbar facets. Thebioactive membrane can be made of a variety of materials including, forexample, demineralized bone matrix, a flexible collagenous polymer and asemi-solid putty or a viscoelastic matrix. This membrane can beintroduced into the prepared facet joint, virtually filling it andresulting in an increase in the surface area for fusion.

According to certain embodiments, a drill may be used to create one ormore hole(s) for inserting a screw, staple, or other fastening devicefor assisting in retaining the bioactive membrane material. A drill holewhich traverses the facet joint and the bioactive material may alsoserve as a conduit through which semi-liquid or liquid materials can bedirectly placed in contact with the biomembrane. These combinedmaterials can stimulate the bone formation process, for example, byadding substrate such a bone morphogenic protein, platelet rich plasmaconcentrate, or growth hormone, directly inoculating the joint-encasedmembrane. In a similar strategy, the painful small joints of the bodycan be so treated where amenable to fusion. One can use this strategy tofuse the interphalangeal joints of the fingers or toes by preparing thecartilage surface of the joint as describe above, and in the sameendoscopic fashion applying the bioactive membrane. The drill hole canthen be used to infiltrate the stimulating fusion concoction. In thesetypes of applications a cancellous bone screw, or other fastening devicemay then be added through the drill hole(s) to stabilize the joint andlock the membrane in an ideal position.

The drill hole that traverses the implant site and bioactive materialmay further serve as a conduit for introducing one or more semi-liquidor liquid materials (including, for example, bone morphogenicsubstrates, bone marrow aspirate, plasma concentrate or other hormonalsubstance) which accelerate the fusion process. In addition,bioresorbable cements, which are currently in use for vertebroplastyprocedures, could be installed through the drill hole portal to affectimmediate joint stabilization. This novel approach to the application ofadditional bioactive materials increases the utility of this approachbecause it allows an epoxy-like separation between the components of thefusion allowing placement of the bioactive membrane prior to theactivation of the fusion process. The applied cancellous screw locks thebioactive membrane in place and stabilizes the respective joint.

Embodiments of the present disclosure are particularly suited forsituations where anterior fixation or a rigid system is already in placein the anterior column of the spine. The literature reveals that a threelevel instrumented anterior cervical fusion will develop apseudoarthrosis in at least one level up to 50% of the time. The use ofsupplemental posterior fixation increases the likelihood of the fusionsucceeding >90% of the time but is fraught with substantial risks ofbleeding and infection, not to mention the patient morbidity associatedwith the severe pain of posterior cervical exposures, the large foreignbody burden (from rods and screws) the permanent muscle damage from softtissue stripping and the expense of additional days in the hospital duesolely to the exposure. If the posterior procedure can be performed withminimal invasion it would justify its use in the reduction of thepseudoarthrosis rate, costs of re-operation rates and patient suffering.

Another unique tool in this disclosure is a bioactive membrane which canbe made of, by way of example but not limitation, demineralized bone,Hydroxyapatite sheet, a flexible Type I collagenous polymer, aviscoelastic matrix, and/or semi-solid putty which can be directlyintroduced into the joint. The prefabricated and pre-shaped bioactivemembranes are specifically designed to fit into the implant site basedupon the regional anatomical differences. This design allows for virtualfilling of the joint with a resultant increase in the chance for fusion.

Another unique strategy afforded by this design is that the facet jointestablishes a key to the anatomy of the vertebral body. Once the facetis located and the biologic membrane with its introducer is insertedinto the joint, reproducible access can be gained to the otherassociated vertebral structures. The spinous process, lamina, pedicle,neural foramen, medial spinal canal and lateral recess can all bereproducibly engaged once the facet joint relationship has beenestablished. Attachment to this landmark allows navigation to othersites for robotic and radio navigation techniques.

Embodiments of the present disclosure present several advantages overthe prior art including, for example, the speed of the procedure, theminimally invasive aspect of the procedure, the ability to introduce theimplant material to the implant site with minimal risk and damage to thesurrounding tissue, the lower risk of infection, more optimally placedvertebral implants, a more stable method of drilling and placing screwsinto an implant and fixation site in a near simultaneous fashion toreduce the likelihood of the implant material becoming dislodged priorto fixation, and fewer tools in a surgical site due to the integrationof an implant placement tool with a drill guide.

Unlike other techniques describing facet joint fusion that employ a leapof faith technology, this process works reproducibly and is safe. Inaddition, unlike other devices, this process keys on the facet joint, astructure that is present from the cervical to the lumbosacral junctionand is, therefore, amenable to treatment for facetogenic problems or forfusion from the C2 to S1 levels. Other techniques recognize theirlimitation and describe fixation of the lumbar or the cervical spineonly, let alone simultaneous fusion and stabilization of the spine atall levels.

One having skill in the art will appreciate that embodiments of thepresent disclosure may be constructed of materials known to provide, orpredictably manufactured to provide the various aspects of the presentdisclosure. These materials may include, for example, stainless steel,titanium alloy, aluminum alloy, chromium alloy, and other metals ormetal alloys. These materials may also include, for example, PEEK,carbon fiber, ABS plastic, polyurethane, rubber, latex, syntheticrubber, and other fiber-encased resinous materials, synthetic materials,polymers, and natural materials.

One having skill in the art will appreciate that embodiments of thepresent disclosure may be controlled by means other than manualmanipulation. Embodiments of the present disclosure may be designed andshaped such that the apparatus may be controlled, for example, remotelyby an operator, remotely by an operator through a computer controller,by an operator using proportioning devices, programmatically by acomputer controller, by servo-controlled mechanisms, byhydraulically-driven mechanisms, by pneumatically-driven mechanisms orby piezoelectric actuators.

Another unique tool in the present disclosure is a cannula having ashape other than round (e.g., oval, pointed, square cornered, egg-shapedetc.) and having an end (e.g., the end inserted into the patient, distalfrom the user) that is angled and/or shaped to be ideally seated in asurgical site. Asymmetrical cannulas may allow visualization of thefacet joint (DePuy has apparently described oval cannulas). An“egg-shaped” cross section may allow for the best view of the facetjoint and minimizes the medial-lateral dissection that a round cannulawould require.

Still other aspects of the invention are directed to cannula instrumentsthat have a patient contacting end that is adjustable to assume apredetermined conformation. Thus, in one embodiment, material forms thetip end that comes into contact with bone, tissue, and particularly nearespecially nerve tissue, with such cannula end material being malleableto an extent necessary for the surgeon to mold the end conformation suchthat it achieves desired avoidance of particular structures encounteredin any particular surgery. Thus, if a bony outcropping, a nerve fiber,etc. is perceived by the surgeon, the cannula tip end can be adjusted toavoid undesired contact or interference with such tissues or structures.In particular embodiments, the ability to adjust the geometricparameters of the tip end is achieved by manipulation of the other endof the instrument. For example, providing a turnable component at theopposite end of the instrument, the shape of the other end of theinstrument (i.e. the end inserted into the patient) can be adjusted toeither expand circumference, reduce circumference, render the openingmore or less oblong, etc. In such a manner, it is possible to avoidhaving to remove the instrument or cannula from the patient's site toadjust the morphology of the instrument or cannula operating end, thussaving time, avoiding undesired reinsertion procedures, etc.

Another aspect of the present invention relates to employment of RFenergy in combination with a conductive bone fill material in order topolymerize the surface of an inflow plume in order to control thegeometry of the fill material. For example, if a surgeon employspolymethylmethacrylate (PMMA), there is a potential for leakage,resulting in undesired complications. Thus, one aspect of the presentinvention involves the treatment of vertebrae and related disc spacesand joints to provide a greater degree of control over the introductionof bone support material in that is designed to provide better outcomes.In this regard, Patent Publication No. 2009/0275995 to Truckai isincorporated herein in its entirely by this reference.

The present disclosure and the embodiments described herein have uniqueintegration of fusion and stabilization using a minimally invasiveapproach. The technique further allows the preparation of the majorityof facet joints in any area of the spine. Furthermore, the same processcan be applied to other joints in the body and/or in veterinaryapplications for the spine and peripheral minor and major joints. Onehaving skill in the art will appreciate that this can be achieved byplacing the pre-formed biological material complex into the joint afterthe joint is prepared with the associated drill guide jig and thenapplying a screw across the joint as described above. Furthermore, andas described herein, several aspects of tools and methods of the presentdisclosure including, for example, the angle of the head, the drill bit,the screw type, the bioactive material and the cannula size, aredependent upon the particular anatomy of the patient, the joint and theimplant site. A specific application of this technique would be to theinterphalangeal joints of the fingers or toes to treat conditions ofpainful osteoarthritis.

The Summary of the Invention is neither intended nor should it beconstrued as being representative of the full extent and scope of thepresent disclosure. The present disclosure is set forth in variouslevels of detail in the Summary of the Invention as well as in theattached drawings and the Detailed Description of the Invention and nolimitation as to the scope of the present disclosure is intended byeither the inclusion or non-inclusion of elements, components, etc. inthis Summary of the Invention. Additional aspects of the presentdisclosure will become more readily apparent from the DetailedDescription, particularly when taken together with the drawings.

The above-described benefits, embodiments, and/or characterizations arenot necessarily complete or exhaustive, and in particular, as to thepatentable subject matter disclosed herein. Other benefits, embodiments,and/or characterizations of the present disclosure are possibleutilizing, alone or in combination, as set forth above and/or describedin the accompanying figures and/or in the description herein below.However, the claims set forth herein below define the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the disclosure andtogether with the general description of the disclosure given above andthe detailed description of the drawings given below, serve to explainthe principles of the disclosures.

It should be understood that the drawings are not necessarily to scale.In certain instances, details that are not necessary for anunderstanding of the disclosure or that render other details difficultto perceive may have been omitted. It should be understood, of course,that the disclosure is not necessarily limited to the particularembodiments illustrated herein.

FIG. 1A is a top elevation view of two adjacent cervical vertebrae;

FIG. 1B is a cross sectional view of a facet joint of the adjacentcervical vertebrae of FIG. 1A;

FIGS. 2A-2D are side elevation views of a variety of rasps and curettesthat may be used to remove the cartilage and other tissue from betweenthe vertebrae in the facet joint;

FIG. 3A is a side elevation view of an apparatus for providing animplantable material to the implantation site;

FIG. 3B is a front elevation view of the apparatus of FIG. 3Aillustrating one example of how the implantable material is coupled tothe head of the apparatus;

FIG. 4A is a side elevation view of the apparatus of FIG. 3A with adrill guide attached to the shaft of the apparatus;

FIG. 4B is a side elevation view of the apparatus of FIG. 3A where thedrill guide is positioned above the drill site on the facet joint ofFIG. 1B, and a drill has been placed in communication with the drillguide to create a hole through the facet joint;

FIG. 4C is a detailed side elevation view of the facet joint of FIG. 1Bafter a screw has been secured to the facet joint;

FIG. 5A is a top elevation view of two adjacent vertebrae with animplantable material and screw inserted into the joint, and with theapparatus of FIG. 3A removed from the site;

FIG. 5B is a side elevation view of the two vertebrae of FIG. 5A withthe implantable material and screw inserted into the joint;

FIG. 6A is a front elevation view of an alternative embodiment of theapparatus of FIG. 3A, which illustrates the head having a partiallyhollow shaft that is inserted into the shaft of the apparatus;

FIG. 6B is a side elevation view of the apparatus of FIG. 6A, whichillustrates the head having a partially hollow shaft that is insertedinto the shaft of the apparatus;

FIG. 7A is detailed front elevation view of the assembly between thehead of the apparatus and the partially hollow shaft of the apparatusaccording to one embodiment of the present disclosure;

FIG. 7B is the side elevation view of the assembly between the head ofthe apparatus and the partially hollow shaft of the apparatus shown inFIG. 7A;

FIG. 7C is a top elevation view of the partially hollow shaft and thehead of the apparatus of FIG. 7B;

FIG. 8 is a side elevation view of a facet joint after a screw has beensecured to the facet joint and the shaft of the apparatus has beenremoved from the head of the apparatus;

FIG. 9A is a side elevation view of a facet screw according to oneembodiment of the present disclosure;

FIG. 9B is a top elevation view of a facet screw showing the head of afacet screw according to one embodiment of the present disclosure;

FIGS. 10A-10C are side elevation views of apparatus according toalternative embodiments of the present disclosure;

FIGS. 11A-11F are various views of a surgical cannula and dilators thatare used in conjunction with certain embodiments of the presentdisclosure;

FIGS. 12A-12F are various views of fastening devices for fixation ofvertebrae, along with the surgical cannula used in conjunction withcertain embodiments of the present disclosure;

FIGS. 13A-13D are various views of a cervical spine fastening device forfixation of vertebrae, along with the apparatus and implant of FIG. 3B;and

FIGS. 14A-14B are various views of a lumbar spine fastening deviceaccording to one alternative embodiment of the present disclosure.

DETAILED DESCRIPTION

According to various embodiments described herein, the presentdisclosure relates to an apparatus with a handle and a forked head onthe distal end of the handle, which may be used to grasp bioactive orother implant material and introduce the material to an implant site.The shaft of the apparatus is shaped so as to allow the affixation of adrill guide and drill while simultaneously holding the implant materialin the implant site. Various other tools include dilators and cannulathat are designed to improve accessibility and efficiency in implantingthe material, as well as reduce trauma to the patient, includinglimiting the risk of ischemic injury due to the displacement of muscleor other tissue when accessing the implant site. In addition to thesetools, fastening devices such as screws, hooks, clamps, rings, clasps,bolts and/or staples such as those described herein may also be used tosecure the bioactive or other implant material to the implant site. Oneaspect of the invention is the near simultaneous implanting of materialand fixation of a facet joint accomplished by using the tool(s)described herein. Other aspects of the present disclosure are describedin detail below.

Although certain embodiments of the present disclosure may includevarious tools to be used with various head shapes and configurations aswell as shaft lengths and shaft configurations, preferred embodiments ofthe present disclosure are depicted in FIGS. 3A-14B. FIG. 3A illustratesan apparatus for implanting an implantable material, preferablycomprising a forked end and a passively flexible distal shaft. Furtherdescription of this apparatus in its varying embodiments is providedbelow.

One aspect of the present invention is to provide tools for use withimplants and/or fastening devices, all of which are anatomicallycorrect, which means are shaped and sized to conform to the specificanatomy of the joint they are intended to be used with. FIG. 1A is aview of the implant site which consists of two adjacent vertebrae 20. Asillustrated, portions of the vertebrae 20 have been deburred and shapedin preparation for implantation. FIG. 1B is a cross sectional view of afacet joint 22 between vertebrae 20 which is the implantation site. ThisFIG. 1B further illustrates a facet joint that has been prepared forsurgery. As can be appreciated, the tissue has been shaped to allowaccess to the implantation site, and allows application of a fixationdevice.

FIGS. 2A-2D depict various rasps 24, 26 and curettes 28, 30 that may beused by a surgeon to remove tissue from the implant site or surroundingarea and prepare the implant surface. These tools may be of varyinglengths and shapes to aid the surgeon in introducing the tool to theintended site in a minimally invasive manner, such as via a cannulathrough a minor incision in the patient. FIG. 2A-2D include anillustration of one rasp with a superior abrasive surface 24, one raspwith an inferior abrasive surface 26, one curette with a superiorcleaning surface 28, and one curette with an inferior cleaning surface30. These and other tools are often used for preparing the surfaces ofthe vertebrae and corresponding joints prior to implanting one or moreimplantable materials.

According to one embodiment, an improved apparatus or tool is disclosedfor assisting in the fixation of adjacent vertebral bodies, whichcomprises a handle, an elongated shaft, and a head that selectivelygrasps, for example, an implantable material which is adapted to beinserted into the joint space between two or more intervertebral bodies.The head of the apparatus can be any of a plurality of shapes, forexample, an arcuate shaped head, where the head is asymmetricallysecured to the distal shaft, such as the apparatus of FIGS. 3A-3B.Alternatively, the head may be symmetric about the point it is securedto the distal shaft.

The head may be further comprised of a variably rigid material designedto allow the bioactive material or other implant to be, for example,frictionally or mechanically held in place, and released uponapplication of a particular force. In another embodiment of theapparatus, the head may be made of a semi-flexible material that iscapable of grasping the bioactive material and releasing the bioactivematerial when a particular force is applied, for example, a force in aparticular dimension. Alternatively, for example, the head may beselectively capable of grasping/releasing the bioactive material once aparticular torque is transmitted from the shaft to the head of theapparatus.

FIG. 3A is a side elevation view of the apparatus 32 according to oneparticular embodiment of the present disclosure. As illustrated, thehead 36 of the apparatus 32 is set at an angle. This angle aids thesurgeon in introducing, for example, the bioactive material 40 to theimplant site. In a preferred embodiment the angle is fixed but accordingto alternate embodiments the angle is variable and may be set by theuser. The proximal portion of the shaft 34 is relatively inelastic, duein part to the fact that the apparatus 32 also serves in one embodimentto brace a drill guide (as illustrated in FIG. 4A). The apparatus 32 ofFIG. 3A depicts a fixed angle head 36 with a flexible distal shaft 34,which may extend approximately 4-12 inches depending on the anatomy ofthe patient and the area of the spine (lumbar, thoracic, cervical) to beoperated on.

In another embodiment of the present disclosure, the head of theapparatus is angled and/or shaped to allow ideal access and placement ofthe implant in the joint. For example, the angle and shape of the headrelative to the shaft may be optimized for a particular implant site.The angle, for example, may be selectively variable to accommodate theanatomical orientation of the disc space or joint, or permanentlyaffixed at such angle. This angle may further depend on the specificvertebrae that form the implant site. Since the spinal column is acurved structure, angle requirements may differ with each implant site.The angle may also depend on which side of the vertebrae the implant isoccurring, whether the surgeon is right or left handed, the approachtaken, etc.

FIG. 3B is a front elevation view of an embodiment of the presentdisclosure. This figure depicts an apparatus 32 according to oneembodiment of the present disclosure with a forked head 38. The forkedhead 38 comprises a plurality of tines and is sized and shaped toreceive a piece of bioactive material 40 that is also sized and shapedso as to be complementary to the forked head 38. One skilled in the artwill appreciate that the interior surface of the tines of the forkedhead 38 may have a groove or a track, and that there may be more thantwo tines without departing from the inventive nature of this embodimentof the disclosure. The corresponding outer surface of the bioactivematerial 40 may have a groove or a track to correspond to the interiorsurface of the forked head. This groove or track will help secure thebioactive material 40 in the apparatus 32, but still permit thebioactive material 40 to become dislodged when it is in a desiredposition or when a certain force is applied to the head/shaft 38/34 asdescribed above. In a preferred embodiment the bioactive material 40 isin the form of a sheet or membrane.

In another embodiment of the present disclosure, the head may bepre-fitted with, for example, bioactive material in such a manner sothat the material can be easily manipulated into the facet joint (asopposed to having to coat or infuse a membrane with bioactive materialimmediately prior to inserting the implant). The forked end may have amechanism that enables it to release the material once a facet screw hassecured the material in the joint. The apparatus may be constructed sothat the forked end can be manipulated, by way of the flexible shaft, inat least one dimension relative to the shaft, such as by guide-wires,pivot points or similar mechanisms know in the art. The apparatus mayfurther be constructed to permit the forked end to comprise a firstorientation, wherein the bioactive material is retained by the head ofthe apparatus, and a second orientation, wherein the bioactive materialis released from the head of the apparatus. According to thisembodiment, the surgeon may selectively retain or release the bioactivematerial by operation of the apparatus.

According to one embodiment of the present disclosure, the head itselfmay be selected from one or more bioactive materials, such that the headis the implant. This bioactive implant may further comprise anabsorbable band, which preferably attaches to the shaft via a resorbablehex-shaped connection. According to alternate embodiments, the head mayfurther comprise multiple absorbable bands which assist in attaching thehead to the shaft. This configuration provides an implant that isdistinguishable from other spinal implants, which are made exclusivelyof a single type of material (e.g., bone, autograft bone, allograft bonegraft, etc.) According to yet an another alternate embodiment, thebioactive implant material comprising one or more absorbable bands whichattaches to the shaft via a resorbable hex-shaped connector may beprovided with a instrument head that does not remain in the patient withthe implant material, but that can serve as a conduit for bioactivematerial inoculation.

FIG. 4A is a side elevation view of the cross section of the joint wherethe apparatus which has been placed in the implant site. The figureillustrates the head 36 of the apparatus which has been inserted intothe facet joint between two adjacent vertebrae 20. The apparatus haspositioned the bioactive material (via the head 36) ideally in the jointspace to span the width of the joint. According to certain embodiments,a drill may be used to create one or more hole(s) for inserting a screw,staple, or other fastening device for assisting in retaining thebioactive membrane material. A drill hole which traverses the facetjoint and the bioactive material may also serve as a conduit throughwhich semi-liquid or liquid materials can be directly placed in contactwith the biomembrane. These combined materials can stimulate the boneformation process, for example, by adding substrate such as bonemorphogenic protein, platelet rich plasma concentrate, or growthhormone, directly inoculating the joint-encased membrane.

In a similar strategy, the painful small joints of the body can be sotreated where amenable to fusion. One can use this strategy to fuse theinterphalangeal joints of the fingers or toes by preparing the cartilagesurface of the joint as describe above, and in the same endoscopicfashion applying the bioactive membrane. The drill hole can then be usedto infiltrate the stimulating fusion concoction. In these types ofapplications a cancellous bone screw, or other fastening device may thenbe added through the drill hole(s) to stabilize the joint and lock themembrane in an ideal position.

FIG. 4A also depicts a drill guide 42 which has been affixed to thestiff, proximal portion of the shaft 34 of the apparatus. FIG. 4Afurther illustrates that the drill guide may be selectively positionedalong the shaft 34 of the apparatus in ideal preparation for the drill,either before the apparatus has been placed inside the patient or duringthe surgical procedure.

FIG. 4B is a side elevation view of the apparatus in the joint, and adrill guide 42 which is attached to the shaft 34 of the apparatus andhas been placed adjacent to the bone and implant site, and a drill 46which has been placed in the drill guide 42. The figure illustrates howthe drill guide 42, coupled with the apparatus, isolates the implantregion and enables the drill 46 to securely and predictably create ahole into the joint. One skilled in the art will appreciate that thedrill guide 46 (and drill bit 44) have been appropriately selected toenable a hole of a specific length and gauge to be made in both adjacentvertebrae 20. In order to provide adequate fixation of the two bones, itis necessary to make a hole in both adjacent vertebrae 20.

FIG. 4C is a side elevation view of the joint after the drill and drillguide have been removed, and after a facet screw 48 has been insertedinto the joint. FIG. 4C depicts how the facet screw 48 has beenassembled to the joint so as to secure the bioactive material in thejoint. This figure also depicts the apparatus still assembled to thebioactive material, and thus still located in the implant site. Thefacet screw 48 may penetrate just the bioactive material, or thebioactive material and the head 36 of the apparatus, depending on theapplication. One skilled in the art will appreciate that the facet screw48 has been appropriately sized to span the width of the implant andprovide adequate penetration into the adjacent vertebra 20 to provideadequate fixation.

FIG. 5A is an inferior elevation view of the implant site which consistsof two adjacent vertebrae 50. As illustrated, the facet screws 51 havebeen assembled to the joint, and the apparatus has been removed from theimplant site. As described above, the apparatus along with the forkedhead may be detached from the bioactive material and thus removed fromthe implant site by selectively detaching the apparatus from thematerial, or by passive means which may include applying a torque to theapparatus or applying force in a particular direction which separatesthe forked head from the bioactive material.

FIG. 5B is a cross sectional view of the joint after a completed implantand fixation. The figure illustrates that the drill and drill guide havebeen removed, a facet screw 51 has been inserted into the joint, theapparatus has been removed, and the bioactive material 40 has beensecured in the joint. The securing of the bioactive material 40 to thejoint is in such a manner so as not to interfere with the removal of theapparatus, the forked head or other tools described herein, whichfurther reduces the chance of trauma or ischemic injury to the patient.

According to one embodiment of the present disclosure, a method ofposterior spinal fixation is provided, which includes using a deviceunder microscopic control or loupe magnification to burr off the bottomof the facet joint. Curettes and rasps of the type described herein maybe used to prepare the facet joint and to create a bleeding surface.Then the surgeon may employ a tool, preferably comprising a forked endand a flexible distal shaft, fitted with bioactive material, to insetand place the bioactive material between the leaves of the joint. Next,a drill guide is lowered over the shaft of the tool until it is adjacentto the facet joint. Then a drill is inserted through the drill guide tocreate hole(s) through the facet joint. A specially designed screw orother fastening device is then assembled through the hole(s) orotherwise adjacent the facet, thereby trapping the bioactive material inthe joint. The forked tool is then removed, leaving the bioactivematerial in the joint space. This method is accomplished in a minimallyinvasive manner to provide near-simultaneous fixation of the vertebralbodies surrounding the facet joint.

FIG. 6A is a front elevation view of an embodiment of the presentdisclosure. This figure illustrates an aspect of this embodiment wherethe entire head 52 of the apparatus comprises the implant material(along with membrane 40). FIG. 6B is a side aspect view of an embodimentof the present disclosure, and it further illustrates the angle betweenthe shaft of the embodiment and the surface of the head. According tothis embodiment, the head 52 is inserted and remains in the joint afterthe shaft 34 of the apparatus has been selectively detached from thehead 52 and then removed from the patient. In this orientation, theapparatus requires a connection between the shaft 34 and the head 52, asopposed to the head 52 and the bioactive material 40. This connectionmay be comprised of a pin connection, a ball and socket connection, ahexagonal shaped connection, a magnetic connection, or other similarconnecting means.

FIG. 7A is an exploded front elevation view of an embodiment of thepresent disclosure where the entire head of the device comprises theimplant material. This figure illustrates one embodiment of the presentdisclosure where the detachment of the head from the shaft 34 of theapparatus is demonstrated as being achieved through the disengagement ofthe stem 54 from the shaft 34, in a telescoping manner. As illustrated,most, or substantially all of the head may be comprised of bioactivematerial. Referring now to FIGS. 7A and 7B, according to this embodimentthe head of the apparatus is comprised of a substantially flat,spatula-shaped component 40, which is in communication with a stem 54.The shaft connection component of the head is designed such that itassembles to a distal end of the shaft of the apparatus. As illustratedin FIG. 7B, the shaft 34 of the apparatus is manufactured with a hollowspace or groove such that the stem 54 of the head engages to the hollowspace of the shaft 34 of the apparatus. The shaft 34 of the apparatusmay, alternatively, be manufactured with a plunger that selectivelypushes the stem 54 of the head out of the hollow space, effectivelydisassembling the head from the shaft 34 of the apparatus. One havingskill in the art will appreciate that there exist other methods ofselectively attaching and detaching the head from the shaft 34 of theapparatus.

Thus, according to one embodiment of the present disclosure, the graftmaterial for implanting into the patient may be prefabricated, andcombined with a semi-rigid material. This composite material may have ahexagonal end that fits into the shaft and/or handle of the drill guidesection, which allows introduction of the material into the joint anddetachment of the grafting material from the introduction tool. Thehexagonal end has a built-in angle corresponding to the angle of thefacet joint. Preferably, the angle is approximately 45 degrees in thecervical spine, approximately 90 degrees in the thoracic spine, andapproximately 180 degrees in the lumbar spine.

The prefabricated osteobiologic material and integrated tool headprovides a unique combination that allows for ease of insertion andmaximizes the grafting surface area. The handle portion may be an inertnon-absorbable material including, for example, nylon or slowlyabsorbing poly gel acetate, either of which may have the attachment ofbiomaterial incorporated. By providing a resorbable material thatattaches to the bioactive implant material, the resorbable material mayalso serve as a conduit for inoculation of BMP, bone marrow aspirateconcentrate or other hormonal materials. The resorbable material mayfurther provide a conduit for introducing other materials such asmetabolic stimulators. The extra-articular section of the composite canbe trimmed at the joint surface once the joint has been stabilized bythe screw, which further secures the grafting material in place.

FIG. 7C illustrates a cross sectional view of the stem 54 of the head ofthe apparatus according to this embodiment. As illustrated, the stem 54has a hexagonal shape. One having skill in the art will appreciate thatthe shaft 34 of the apparatus will have a complementary hexagonal shapeor other shape hollow opening which engages the stem 54 of the head (seefor example a twelve point socket) of the apparatus. One having skill inthe art will also appreciate that the stem 54 of the head need not behexagonal in shape. It may, for example, be circular, semicircular,flat, square or triangular. The shaft of the head may also be, forexample, symmetric or asymmetric. One having skill in the art willappreciate that the complementary aspect of the shaft 34 of theapparatus will be shaped to allow the stem 54 to assemble with the shaft34 of the apparatus. FIG. 7C also shows a conduit 55 through whichbiologic stimulating materials can directly inoculate the membrane/cageafter it is inserted within the facet joint.

FIG. 8 is a side elevation view of an embodiment of the presentdisclosure where the head 40 of the apparatus is secured in the implantsite by the vertebrae 20 and facet screw 51, and the shaft 34 of theapparatus is detached from the head.

FIG. 9A is a side elevation view of a facet screw 48 and washer assembly49 according to one embodiment of the present disclosure, which may beused to assist in fusing the vertebrae or other aspects of the joint andthe implant material. In the illustration, the facet screw has a laggedthread, which enables the selective compression of the joint regionduring assembly of the implant to the joint. This type of threading maynot be applicable to all types of implants. One having skill in the artwill appreciate that different lengths, threads, spacing and lags may beused. FIG. 9B is a top aspect view of the facet screw 48 according tothis embodiment. This illustrates a screw with a rounded, allen-typehead. One having skill in the art will appreciate that the facet screw48 may have a head comprising other form factors. It is another aspectof the present disclosure that the screw 48 may be hollow, having anopening at or near the head of the screw 48, and having at least oneopening on the shaft of the screw 48. The openings at or near the headand on the shaft are designed to permit fluid communication between thehollow interior of the screw 48 and the outside of the screw 48. Screw48 preferably includes at least one washer 49.

It is thus one aspect of the present disclosure that at least oneopening on the shaft of the screw be positioned such that bioactivematerial and/or other material can be injected into the joint space orimplant site by urging the material into the screw head, through thehollow interior of the screw and out the at least one opening on theshaft of the screw. One having skill in the art will appreciate that theat least one opening on the shaft of the screw may be located in a fluteor flight of the threads, in the lag portion or in the tip. One havingskill in the art will further appreciate the method by which an urgingmechanism may be attached to the end of the screw to urge the bioactivematerial and/or other material into the screw. It is yet another aspectof the present disclosure that the screw is a porous material and/orcomprised of a bioactive material. In still yet another aspect of thepresent disclosure, the screw may have a coating or impregnated withbioactive material.

In another embodiment of the present disclosure, the head of theapparatus is angled and is shaped to allow ideal access and placement ofthe implant in the joint. For example, the angle and shape of the headrelative to the shaft may be optimized for a particular implant site.The angle, for example, may be selectively variable or affixed. Thisangle may further depend on the specific vertebrae that form the implantsite. Since the spinal column is a curved structure, angle requirementsmay differ with each implant site. The angle may also depend on whichside of the vertebrae the implant is occurring.

FIGS. 10A-10C are side elevation views of one embodiment of the presentdisclosure illustrating that the angle between the shaft of the head andthe head determines the overall angle between the shaft of the apparatusand the head. The figures further illustrate that different angles maybe appropriate for different joints. One having skill in the art willappreciate the bone markings and anatomy of the various vertebrae andjoints, and understand the ideal angle between the shaft of the head andthe head for a given procedure or surgical site. FIG. 10A illustrates,for example, that an approximately 45 degree angle may be appropriatefor use in a cervical joint. FIG. 10B illustrates, for example, that anapproximately 90 degree angle may be appropriate for use in a thoracicjoint. FIG. 10C illustrates, for example, that the angle may be variableup to an approximate 180 degree angle, which may be appropriate for usein a lumbar joint, for example. FIGS. 10A-10C taken together illustrateanother aspect of the present disclosure, which is that the shaft of theapparatus may be applied in several different implant scenarios, andthat only the head of the apparatus needs to be appropriately selected.

Another unique tool in the present disclosure is a cannula having ashape other than round (e.g., oval, pointed, square cornered, etc.) andhaving an end (e.g., the end inserted into the patient, distal from theuser) that is angled and/or shaped to be ideally seated in a surgicalsite. Asymmetrical cannulas may allow visualization of the facet joint(DePuy has apparently described oval cannulas). An “egg-shaped” crosssection may allow for the best view of the facet joint and minimizes themedial-lateral dissection that a round cannula would require.

Still other aspects of the invention are directed to cannula instrumentsthat have a patient contacting end that is adjustable to assume apredetermined conformation. Thus, in one embodiment, material forms thetip end that comes into contact with bone, tissue, and particularly nearespecially nerve tissue, with such cannula end material being malleableto an extent necessary for the surgeon to mold the end conformation suchthat it achieves desired avoidance of particular structures encounteredin any particular surgery. Thus, if a bony outcropping, a nerve fiber,etc. is perceived by the surgeon, the cannula tip end can be adjusted toavoid undesired contact or interference with such tissues or structures.In particular embodiments, the ability to adjust the geometricparameters of the tip end is achieved by manipulation of the other endof the instrument. For example, providing a turnable component at theopposite end of the instrument, the shape of the other end of theinstrument (i.e. the end inserted into the patient) can be adjusted toexpand circumference, reduce circumference, render the opening more orless oblong, etc. In such a manner, it is possible to avoid having toremove the instrument or cannula from the patient's site to adjust themorphology of the instrument or cannula operating end, thus saving time,avoiding undesired reinsertion procedures, etc.

FIGS. 11A-11F are various views of certain embodiments of a surgicalcannula that may be used in conjunction with certain aspects of thepresent disclosure. FIGS. 11A and 11B show side elevation views ofcertain embodiment of the cannula 60 and 62 respectively. FIG. 11A showsa cannula 60 having a bottom opening that is angled oblique to the topopening. FIG. 11B shows the cannula 62 having a bottom opening that issubstantially parallel to the top opening. As shown in FIGS. 11A-11B,cannula 60, 62 may be in correspondingly larger or smaller form factorsso that they may become nested within one another for facilitatinginsertion in the patient.

FIG. 11C shows a top cross-sectional view of the cannula 64. FIG. 11Cshows the cannula 64 having an elliptical cross-section. In oneembodiment, the ellipse has a width of about 20 millimeters in its majoraxis, and a width of about 16 millimeters in its minor axis. It will beappreciated that the cannula cross-section may be of a different sizeand have a different shape including, for example, an oval, a rectangle,a square, a rhombus, a trapezoid, a parallelogram, a polygon and agenerally oblong shape such as an egg or football shape. As will beappreciated by one having skill in the art, the cross-sectional shape ofthe cannula 60 permits the user to employ instruments in the cannulathat require movement or manipulation in one direction, preferably alongthe major axis, but to a lesser extent in the other direction. Theoblong shape of the cannula 60 would permit, for example, the rasps andcurettes in FIG. 2 to be manipulated and used in a joint in a minimallyinvasive fashion. Similarly, the tool 32 can be manipulated and used ina joint even with the head 36 at any angle relative to the shaft. Onehaving skill in the art will appreciate that the dimensionalrequirements of the cannula 60 will vary based on the length of thecannula, and the items or tools being inserted therein.

FIG. 11D shows two vertebrae 20 and a view of the footprint made by acannula 60 in one embodiment of the present disclosure. As will beappreciated, the cannula 60 provides access to adjacent facets of twoadjacent vertebrae. The oval or elliptical shape of the cannula 60,however, allows the procedure to be performed in a minimally invasivefashion by reducing the incision required to gain access to the surgicalsite and the reducing the tissue exposed during the procedure. FIG. 11Eis a side aspect view of the cannula 60 placed over two adjacentvertebrae 20 separated by a joint space. The view in FIG. 11E is theside aspect view of the cannula 60 in, for example, FIG. 11D. FIG. 11Eexemplifies another advantage provided by certain embodiments of thecannula 60 in the present disclosure in that it provides optimal accessto a surgical site that may have anatomy or bone features that make itdesirable to have, for example, an angled and/or curved end to thecannula. One having skill in the art will further appreciate that anideally shaped cannula 60 will allow the user to more safely andreliably access the surgical site and will reduce the risk of injury tothe surrounding tissue.

FIG. 11F shows the shaft and cross-sectional or end views of variousdilators 66. The various dilators 66 shown are of various sizes, havingvarious lengths and cross-sectional areas. As can be seen by thecross-sectional or end view of the dilators 66, the dilators 66, likethe cannulae described above have an oval or elliptical shape. Accordingto a preferred embodiment, one or more dilators may be used to dilatethe muscle or other tissue of the patient to access the surgical site. Afirst slender dilator 66 is used to probe through the muscle or othertissue and to locate the desired vertebrae. Once that first slenderdilator 66 is seated, additional dilators 66 may be inserted around thepreviously seated dilator 66 until the desired circumference through themuscle or other tissue is achieved. In this fashion, the first slenderdilator 66 serves as a radiographic marker, and establishes the path forsubsequent dilators 66 of greater circumference than the first slenderdilator 66. This serves to reduce ischemic injury to the patient andreduces the time necessary to locate and access the desired vertebrae.The first slender dilator 66 has a sufficient circumference to be easilyviewed by x-ray or other imaging technology when seating the dilator 66on the desired vertebrae. The dilators 66 are variable in length,preferably ranging from 3-14 cm.

Once the dilators 66 have been used to dilate the muscle tissuesurrounding the path to the desired vertebrae, a cannula 60 may beinserted into the interior circumference of the dilators 66. The cannula60 according to a preferred embodiment is ovoid in shape to permitdissection from caudad to cephalad (as opposed to from medial tolateral) and further accommodate dissection about the facet joint. Aswith the dilators 66, the cannula 60 may be variable in length, rangingpreferably from 3-10 cm, to accommodate varying depths from skin tobone. As mentioned above, the cross-sectional geometry of the cannula ispreferably ovoid in shape, and in a preferred embodiment the majordiametrical axis of the cannula is about 20 mm, and the minordiametrical axis of the cannula is about 16 mm.

Varying embodiments of the cannula described herein may further comprisean angled or sloped surface at one distal end of the cannula foraccommodating access and viewing of an implant site that is not directlybelow the incision. By way of example but not limitation, a surgeon mayuse one or more of the angled cannula shown in FIGS. 11A-11F inconjunction with the dilators 66 described herein to probe through themuscle or other tissue using an angled approach, thereby allowing accessto a specific vertebrae either above or below the vertebrae directlybelow the incision. Once the dilators have been used to clear a paththrough the muscle or other tissue at an angled approach, the angledcannula may be inserted with the angled or sloped surface oriented sothat the angled or sloped surface rests near horizontally against thevertebrae, as shown in the appended Figures. This angled cannula assiststhe access and visibility of additional vertebrae without requiringadditional incisions, and further permits securing fastening devicessuch as screws using an angled approach. As with the other cannuladescribed above, the cross-sectional shape of the angled cannula ispreferably ovoid in shape, and the entire longitudinal length of theangled cannula may be slightly greater than the other cannula describedherein.

Thus, according to one embodiment of the present disclosure, a methodfor fusing one or more facet joints is disclosed, whereby a surgeon mayuse the dilators and cannula described in the preceding paragraphs toaccess a first facet joint, nearly directly underneath the incision, andin particular by using the straight surfaced cannula described above.Once the joint has been treated, the cannula may be removed and thedilators 66 used again but now using an angled approach through themuscle or other tissue to access a different facet joint. Once the firstdilator 66 has located the desired facet joint, additional dilators maybe employed to enlarge the path through the muscle or other tissue, andultimately the angled cannula inserted through the path to the implantsite. Once the second facet joint has been treated the angled cannulamay be removed, and the steps described above repeated to accessadditional facet joints. In this fashion a multi-level fusion may beaccomplished without the need for additional incision, and still permitthe surgeon to achieve a wide viewing area along the surface of thevertebrae, wherein the angled or sloped surface of the angled cannularests nearly horizontally about the surface of the vertebrae.

Referring now to FIGS. 12A-12F, another method for stabilizing the facetjoints of the spine utilizing a minimally invasive approach involves thesame cannula exposure and application of the bioactive membrane.Measurements suggest the size of the membrane/implant is on averageabout 3×9×6 mm in size. The handle or shaft 34 used to direct themembrane into position is hexagonal in cross-section and has a 3 mmdiameter. Once the graft is in position, a pilot hole punch is used tocreate appropriate starting holes in the external facet surface. Then anasymmetric, barbed staple 77 is placed over the shaft 34 so that itcovers and secures the bioactive membrane. Staple 77 may be placed overthe shaft 34 by engagement with a ring 79 located on one side of staple77. The staple 77 may be attached to an impactor 81 which controls therotation of the staple 77 and ensures uniform impaction into the bone.The position of the membrane and resultant position of the shaft 34 helpdetermine the position of the staple 77 which is impacted into bothleaves of the facet joint.

According to an alternate embodiment, a staple, clamp, hook, or otherfastening device may be used for retaining the implant within the facet,either in addition to or in lieu of a facet screw. The staple may bemade of a spring metal. When in its relaxed posture, the staple's topsurface is curved, which angles the asymmetric legs towards one another.When the spring metal staple is placed in its holder, it flattens outthe surface of the staple and the staple legs return to near rightangles. Once the staple is impacted, it tries to return to its relaxedposition, which has the effect of compressing the leaves of the facetjoint against the bioactive implant. In another aspect of the design,the staple is made of a memory metal, such as nitinol. At roomtemperature its legs are at near right angles to its surface. At bodytemperature, the surface of the staple attempts to bend, which drivesthe legs of the staple together. Once implanted, and as the staplewarms, it converts to a compressive loading device.

The staple described according to this embodiment preferably measures 15mm in length, its cephalic end having at least one barb and about 6 mmin length, its caudal end also having at least one barb and about 8 mmin length. Preferably the staples have at least two barbs on each of thecephalic and caudal end. The view from the top shows a generallyasymmetric collar attached to the staple. The collar allows positioningof the staple over the tab of the bioactive membrane which helps hold itin place. The asymmetry of the staple legs is necessary to conform thestaple to the peak of the bony contours of the facet joints, where thesuperior leaf is a peak, and the inferior leaf is a valley. Theasymmetric collar on the staple helps to direct the staple morelaterally, where the bone is thicker and further away from the spinalcord. One advantage of this method and apparatus is that it simplifiesthe fixation of the joint, and avoids having to change or reorient thecannula to apply a drill hole or screw. This method further eliminatesrisk of overdrilling or cracking of the bone due to the length orthickness of the screw.

According to another embodiment, the staple is not secured at all to thebioactive membrane. In yet another embodiment, the bioactive membranemay be permanently attached to the staple, or packaged with the stapleas a unit for implanting and fixating the implant material in the joint.The staple may have two barbs of the same length, or with one barb beingslightly longer than the other barb to accommodate for the anatomy ofthe patient's adjoining facets. Various staples may be used with thisapparatus and method, including staples comprising a series of barbs asopposed to two individual barbs on either end of a collar. The barbs maybe on the inner aspect of the staple legs for the memory metal design oron the outer aspect of the legs. According to yet another embodiment, aninserter may be provided with two “feet” at one distal end that allowsthe staple to attach temporarily to the inserter by placing the “feet”on the collar and between the barbs of the staple. In this manner, theinserter may be used in conjunction with the forked tool for implantingthe bioactive material, or may be placed around the outer circumferenceof the forked tool to allow the implant and fixation to occur nearlysimultaneously. In yet another embodiment, the “feet” may beincorporated in the shaft of the forked tool, thereby eliminating theneed for two separate tools within the narrow cannula.

Referring now in detail to FIGS. 13A-13D, a fastening device accordingto one embodiment of the present disclosure is shown. In FIG. 13A, anasymmetrical staple 100 is shown, having two legs 101, each leg havingtwo barbs, and the central portion 103 of the staple 100 between the twolegs 101 including a tab 105. Referring now to FIG. 13B, the tab 105 maybe inserted into a slot 143 in the bioactive material 140 describedabove, for inserting the staple 100 and bioactive material 140simultaneously using a single tool. As shown in FIG. 13C, the tool maybe comprised of a forked end, with a plurality of tines which engage alateral slot 141 on either side of the bioactive material 140. Thehorizontal slot 143 shown in FIG. 13C is reserved for engagement ofstaple 100, and in particular the tab 105 of the staple 100 shown inFIG. 13A. Referring now to FIG. 13D, the tool, staple, and bioactivematerial are shown as one assembled unit. According to this embodiment,a single tool may secure both the asymmetrical staple 100, and thebioactive material 140, prior to insertion and delivery to the surgicalsite. This permits a surgeon to insert a single tool, which provides thebioactive material 140 to the disc space or facet joint, andsimultaneously position the asymmetrical staple 100 on either side ofthe facet joint. Once the bioactive material 140 and staple 100 are inplace an additional tool may be inserted to drive the two legs 101 ofthe staple 100 into either pre-drilled holes or directly to the surfacesof the vertebrae adjacent the facet joint. Once the staple 100 issecured, it holds the bioactive material 140 in place, and the tool maybe removed without disturbing either the bioactive material 140 or theasymmetrical staple 100.

According to varying embodiments, the asymmetrical staple describedherein may be comprised of a variety of different materials. Forexample, the staple may be made of a spring metal, which has certaincompressive properties, or that is substantially rigid yet flexible tosecure the bioactive material in the facet joint despite movement of theintervertebral bodies surrounding the joint. According to anotherembodiment, the staple may be formed of a memory metal, for example,nitinol, which also exerts a compressive force within the joint. Memorymetal also has the advantage of being able to adjust to the particularanatomy of the patient, the movement of the vertebrae, the distortion ofthe staple during insertion and implant of the bioactive material, andto the bioactive material itself as it fuses with the vertebrae. This isparticularly beneficial when some or all of the implant is made from aresorbable material.

According to yet another embodiment, the staple shown in FIGS. 13A-13Dmay be substantially hollow such that a fast curing epoxy or cement, afast curing bioactive cement, a cell culture, or other biologicallyinert substance may be injected into the substantially hollow staple viathe shaft of the tool, and then ejected out one or more openings at thedistal end of each of the legs 101 of staple shown in FIG. 13A.According to yet another embodiment of the present disclosure, thestaple may be made of a variety of materials, such as demineralized bonematrix, a flexible collagenous polymer, a semi-solid putty, or aviscoelastic matrix. In yet other embodiments the staple may be made ofa common material such as stainless steal, titanium alloy, aluminumalloy, chromium alloy, or other metal or metal alloys. Material that thestaple is comprised of may also include, for example, PEEK, carbonfiber, ABS plastic, polyurethane, rubber, latex, synthetic rubber,and/or other fiber incased resinous materials, synthetic materials,polymers, and natural materials, either in whole or in part. The hollowdesign allows for virtual filling of the staple and/or the pre-drilledholes and/or portions of the joint with the resulting increase in thechance for fusion.

Referring now to FIGS. 14A-14B, a staple 110 for securing adjacentvertebrae in the lumbar spine region is shown. FIG. 14A shows a topperspective view of a lumbar staple 110, which comprises a substantiallyplanar bridge 111, further comprising a central aperture 117, and fourlegs 113 positioned approximately at each corner of the substantiallyplanar bridge 111. The central aperture 117 allows insertion andapplication of a tool, such as the one referred to above in respect toFIGS. 13A-13D. The central aperture 117 also permits the insertion of atamp or other tool after the insertion tool of FIGS. 13A-13D has beenremoved. In a preferred embodiment, the lumbar staple 110 has four legs113, each comprising at least two barbs, although in alternateembodiments more or fewer barbs and/or fewer or more legs may be used.Referring now to FIG. 14B, a side perspective view of the lumbar staple110 of FIG. 14A is shown. As shown in FIGS. 14A and 14B, the lumbarstaple 110 further comprises a collar or ring 121 for coupling to theshaft of an apparatus for introducing the staple 110 simultaneously withthe bioactive material or other implant, and that permits the shaft ofthe apparatus to disengage the staple 110 once it is positioned in thejoint.

Similar to the asymmetrical staple of FIGS. 13A-13D, the lumbar staple110 may be made of a variety of different materials, including springmetal, memory metal (e.g., nitinol), or any of the other materialsreferenced above in connection to the asymmetrical staple. The method ofsimultaneously inserting the staple 110 and the bioactive material orother implant described above in relation to FIGS. 13A-13D also appliesfor the lumbar staple shown in FIGS. 14A-14B.

A variety of other apparatus and methods may be employed in conjunctionwith the various aspects described herein to achieve fusion withoutdeparting from the spirit of the invention, such as the followingapparatus and methods hereby incorporated by reference in theirentireties: U.S. Patent Publication No. 2009/0299411 to Laskowitz, etal.; U.S. Patent Publication No. 2009/0299412 to Marino; U.S. PatentPublication No. 2009/0299477 to Clayton, et al.; U.S. Patent PublicationNo. 2009/0275995 to Truckai, et al.; U.S. Patent Publication No.2009/0287262 to Bertagnoli; and U.S. Pat. No. 7,621,955 to Goble, et al.

While various embodiment of the present disclosure have been describedin detail, it is apparent that modifications and alterations of thoseembodiments will occur to those skilled in the art. However, it is to beexpressly understood that such modifications and alterations are withinthe scope and spirit of the present disclosure, as set forth in thefollowing claims.

The foregoing discussion of the disclosure has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the disclosure to the form or forms disclosed herein. In theforegoing Detailed Description for example, various features of thedisclosure are grouped together in one or more embodiments for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed disclosurerequires more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the followingclaims are hereby incorporated into this Detailed Description, with eachclaim standing on its own as a separate preferred embodiment of thedisclosure.

Moreover, though the present disclosure has included description of oneor more embodiments and certain variations and modifications, othervariations and modifications are within the scope of the disclosure,e.g., as may be within the skill and knowledge of those in the art,after understanding the present disclosure. It is intended to obtainrights which include alternative embodiments to the extent permitted,including alternate, interchangeable and/or equivalent structures,functions, ranges or steps to those claimed, whether or not suchalternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

1. A method of spine fusion comprising: preparing a facet joint toreceive an implantation device; inserting a tool into the facet joint,said tool consisting essentially of a handle, a head associated withsaid handle, said head adapted to grasp a bioactive material, said toolhaving a forked end and a flexible distal shaft, said forked end havingat least two tines at predetermined angles; providing bioactive materialin a predetermined amount, said bioactive material fitted onto saidforked end, and placing the bioactive material into the facet jointusing the tool; creating at least one hole through the bone adjacent thejoint; inserting at least one fixation device through the at least onehole; and wherein the steps of providing bioactive material andinserting at least one fixation device occur in near simultaneousfashion.
 2. The method of claim 1 further comprising the step of:Adjusting the angle between the head of the tool and the shaft of thetool for accommodating the anatomy of the patient and the orientation ofthe vertebrae located at the surgical site.
 3. The method of claim 2wherein the angle is capable of adjustment to approximately 45 degreesfrom the axis of the shaft of the tool for surgery in the cervicalspine, to approximately 90 degrees for surgery in the thoracic spine,and approximately 180 degrees for surgery in the lumbar spine.
 4. Anapparatus for providing fixation of adjacent vertebral bodiescomprising: a handle; an elongated shaft; a head coupled to theelongated shaft; wherein the head further comprises one or more tinesfor grasping, for example, an implantable material which is adapted tobe inserted into the joint space between two or more intervertebralbodies.
 5. The apparatus according to claim 4 wherein the head iscomprised of bioactive material, and wherein the head is inserted andremains in the joint after the shaft of the apparatus is removed fromthe patient.
 6. The apparatus according to claim 5 further comprising atleast one conduit from the elongated shaft to the head comprised ofbioactive material through which inoculation of the implantable materialmay be achieved with one or more activating biomaterials.
 7. Theapparatus according to claim 4 wherein the head is connected to theshaft of the apparatus by connecting means, the connecting meanscomprising means for selectively attaching and removing the head fromthe shaft.
 8. The apparatus according to claim 7 wherein the connectingmeans is comprised of a pinned connection.
 9. The apparatus according toclaim 7 wherein the connecting means is comprised of a ball and socketconnection.
 10. The apparatus according to claim 7 wherein theconnecting means is comprised of a plurality of opposing magneticelements.
 11. The apparatus according to claim 4 wherein the apparatusfurther comprises means for selectively grasping and releasing theimplantable material.
 12. The apparatus according to claim 4 wherein theimplantable material comprises one or more channels which are orientedto contact the one or more tines of the head of the apparatus.
 13. Amethod of fusing one or more vertebral bodies comprising the steps of:Accessing the surgical site by inserting a first probing device followedby increasingly larger cannulae to expand the region in which tooperate; Using curettes and rasps to prepare the surgical site andcreate a bleeding surface about the faces of the joint; Inserting a toolcomprising a forked end and a flexible distal shaft, the forked endfitted with a bioactive membrane, through the cannulae and between theleaves of the joint; Placing at least one drill guide over the shaft ofthe tool and adjacent the joint; Employing a drill inserted through theat least one drill guide to create at least one hole(s) in the joint;Fastening a screw or other like device to the at least one hole(s) andadjacent the facet, thereby trapping the bioactive membrane in thejoint; Removing the forked tool, the cannulae and the at least one drillguide from the patient; Wherein the foregoing steps are accomplished ina minimally invasive manner and provide near-simultaneous fixation ofthe vertebral bodies surrounding the joint.
 14. A screw for joiningvertebrae and at least one implantable material comprising: a head; agenerally cylindrical body with a threaded outer circumference, the bodytapering from the head to a distal end of the screw; wherein an apertureis located on the head of the screw which is in communication with ahollow portion within the generally cylindrical body, which is infurther communication with an aperture at the distal end of the screw;and wherein the screw is operatively associated with at least one toolfor delivering a bioactive material from the tool to the hollow portionof the screw and thereafter ejected from the aperture at the distal endof the screw for the purpose of facilitating fusion of the vertebrae.15. The screw according to claim 14 wherein the hollow portion ispre-filled with bioactive material that is ejected from the screw byoperation of the at least one tool turning the screw into a pre-drilledhole in one of the vertebrae.
 16. The screw according to claim 14wherein the generally cylindrical body of the screw further comprisesone or more additional apertures for ejecting the bioactive materialinto the joint between the vertebrae.
 17. An anatomically correctvertebral staple for joining adjacent vertebrae comprising: at least twolegs comprising a plurality of barbs, one of the at least two legs beinglonger than the other to conform to the posterior of a facet joint; andat least one attachment means for selectively attaching the staple to abioactive material and simultaneously attaching to a insertion tool. 18.The staple according to claim 17 wherein the staple is formed of aspring metal.
 19. The staple according to claim 17 wherein the staple isformed of a memory metal such as nitinol.
 20. The staple according toclaim 17 further comprising a tab extending from a central portionconnecting the at least two legs for coupling with the bioactivematerial.
 21. The staple according to claim 17 wherein the staplecomprises four legs, two legs being longer than the other two legs, andthe four legs connected by a substantially planar bridge for joiningvertebrae in the lumbar spine.
 22. A cannula for inserting into a humanpatient during a minimally invasive spine surgery having an ovoid crosssection for enhancing the view of the facet joint and minimizing themedial-lateral dissection about the portion of the spine accessed by thecannula.
 23. The cannula according to claim 22 further comprising adistal contacting end that is adjustable to form to the contour of theanatomy of the patient's spine.
 24. The cannula according to claim 22wherein the distal contacting end is sloped or angled for accommodatingthe geometry of the facet joint or disc space.
 25. The cannula accordingto claim 22 wherein the cross-section of the cannula is substantially“egg” shaped to permit dissection from caudad to cephalad and to furtheraccommodate dissection about the facet joint.